Connecting an HVAC condensate line to cleanout

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Profound-Tingle-Reoccur, Jul 29, 2020.

  1. Profound-Tingle-Reoccur

    Profound-Tingle-Reoccur New Member

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    Currently, my HVAC condensate line is connected directly through a hole drilled into the top of a plumbing cleanout in my utility room. I hadn't had any issues with this setup until recently when I had a small amount of water backup. I think this connection was the source of the water and that it coincided with the city turning off the water for 1/2 a day.

    What would be the proper way to connect my HVAC condensate line into this cleanout in order to avoid backups? Would it be as simple as adding in a backflow preventer (like a Moen M8086) then wye to the drain line? Or should the condensate line be trapped before the connection? I also see that I don't have the proper slope to the drain and will likely add in a condensate pump.

    Thanks for the help!

    The code in my area states that "a drain line from a HVAC system or equipment shall be indirectly connected to a drainage system".

    I also found the manual for my furnace and although it didn't have diagrams of the proper drainage setup, there were a few general bullets:
    • The drain trap supplied with the furnace must be used.
    • The drain line between furnace and drain location must be constructed of 3/4” PVC.
    • The drain line between furnace and drain location must maintain a 1/4 inch per foot downward slope toward the drain.
    • Do not trap the drain line in any other location than at the drain trap supplied with the furnace.
    • Do not route the drain line outside where it may freeze.
    • If the drain line is routed through an area which may see temperatures near or below freezing, precautions must be taken to prevent condensate from freezing within the drain line.
    • If an air conditioning coil is installed with the furnace, a common drain may be used. An open tee must be installed in the drain line, near the cooling coil, to relieve positive air pressure from the coil’s plenum. This is necessary to prohibit any interference with the function of the furnace’s drain trap.
    IMG_0370.JPEG IMG_0371.JPEG
     
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    You don't really want to do what was done, especially if there's no trap at the outlet as when the fan isn't on, sewer gasses could be coming into the ducts.

    What you'd normally do is have something like a washing machine stand pipe with a trap and the outlet of the drain line feeding into it via an air gap. That might require a condensate pump versus gravity as it is now. If you do have a washing machine stand pipe on the same floor, you could add the pump and run the line over there. Depending on the pump you choose, most of them can handle a fair amount of head (elevation, rise), so you could run the line up near the ceiling to keep it out of the way and prevent damage.
     
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  4. Profound-Tingle-Reoccur

    Profound-Tingle-Reoccur New Member

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    Ok great, I do have a laundry room nearby. So the best option may be to cap the cleanout, then add in a condensate pump and run the drain line through the ceiling and connect it to the drain in the washing machine box?

    61713773300__ADCEE5B2-0A73-4DAA-A518-8F7EF839E8EE.jpeg 61715348580__1F4AF029-5935-4E82-AF7A-1D070C48072E.jpeg 61715402998__D3EA7DB4-2261-44CA-9C0D-5AF6D30A3992.jpeg

    [​IMG]

    Picture of a dual waste on washer added by Terry Love
     
    Last edited by a moderator: Aug 9, 2020
  5. Reach4

    Reach4 Well-Known Member

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    Yes. They sell devices for the purpose. If that is a 1.5 inch standpipe, it is harder than if the standpipe is 2 inch.

    Another possibility would be to put on a branch tee to the lavatory drain, and pump the condensate to just above the trap. If running that line is practical, post a photo of the bottom of the lavatory and its trap.
     
  6. Profound-Tingle-Reoccur

    Profound-Tingle-Reoccur New Member

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    That solution might actually be easier as it's just a sheet of drywall between the bathroom and the utility room and there seems to be lots of room above the trap to add in a branch tee.

    IMG_0382.jpeg
     
  7. wwhitney

    wwhitney Active Member

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    I think it's usually done with a tubular branch tailpiece. I'm not used to seeing the trap adapter upstream of the trap, but you could cut back the vertical ABS, put on a lower trap adapter, and add the tubular branch tailpiece. They are available in both 1-1/4" and 1-1/2".

    If your condensate is from combustion (condensing furnace), and you don't have a neutralizer, then it is acidic. So you'll need to use only plastic piping, and get a condensate pump rated for the acidic condensate (maybe they all are, I don't know). Not sure what the requirements are on disposing of acidic condensate in the DWV system, seems like if there is cast iron anywhere downstream of that lavatory, it's theoretically possible for the condensate to corrode it.

    Cheers, Wayne
     
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  8. Jeff H Young

    Jeff H Young In the Trades

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    pretty easy to put a wye in for the condensate at the lav . get a tubular y branch tailpiece couple hose clamps and a foot or 2 of hose
     
  9. Reach4

    Reach4 Well-Known Member

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    Oatey 817ETBN-1 is a 1-1/4 tailpiece. [​IMG]
    1-1/4 is a lot harder to find than 1-1/2 and costs more.
     
  10. Jeff H Young

    Jeff H Young In the Trades

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    ok in a nut shell my way under sink would be cut tailpiece at about level with trap arm discard or set aside existing trap adapter, glue new 1 /1/2 trap adapter on, install 1 1/2 wye branch tubular trap with 1 1/4 washer on top . Done with this portion of job
    BTW, your current p trap set up was a good way to plumb under sink. Takes a lot longer at least 5 minutes,costs 2 dollars more , a little more glueing under a cabinet, but much more rugged than tubular of cource how rugged is needed?
     
    Last edited: Jul 30, 2020
  11. Profound-Tingle-Reoccur

    Profound-Tingle-Reoccur New Member

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    Ok great, thanks for all of the responses. So if I have this straight I should remove the trap adaptor & cut out a portion of the vertical ABS. Then install a branch tailpiece it it's place, such as this one, and install a new trap adaptor below it.

    Picture1.jpg

    Now in regards to connecting the tube from the condensate removal pump into the branch tailpiece, the Little Giant pumps I've been looking at all accept a maximum 3/8" ID outlet tubing (I believe this is usually 1/2" OD) to prevent excessive flow back to unit. The branch tailpieces I've found seem to have either a 5/8" or 7/8" OD outlet. What would be the ideal way to connect the pump outlet tube to the branch tailpiece?
     
  12. Profound-Tingle-Reoccur

    Profound-Tingle-Reoccur New Member

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    OK, slight change to a simpler approach. Would it work if I installed a dishwasher wye in the middle of the 1 1/2" vertical ABS, then connect the vinyl pump outlet tube using a universal dishwasher branch connector?

    Dishwasher Wye.jpg ps6469_pef.jpg
     
  13. Reach4

    Reach4 Well-Known Member

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    [​IMG]
    https://www.homedepot.com/p/LTWFITT...licer-Fittings-5-Pack-HF3913R100605/313389273

    Here is an easier to find alternative: 3/8 in. Barb x 3/8 in. MIP Adapter Fitting in brass or plastic.
    [​IMG]
    5/8 ID non-reinforced vinyl tubing can stretch over the 3/8 NTP thread. That MIP fitting is 0.675 inches max od.


    Similarly, 1/2 NTP thread would be max 0.840 and you might be able to stretch 3/4 non-reinforced tubing over that.

    I have no problem with your proposal, but will that rubber gadget that you picture connect to your 3/8 ID tubing? The word "universal" is often too optimistic.
     
    Last edited: Aug 6, 2020
  14. Profound-Tingle-Reoccur

    Profound-Tingle-Reoccur New Member

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  15. DavidDeBord

    DavidDeBord New Member

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    Greetings Profound,

    You have more than One Problem.

    "Live Free or Die" is absolutely correct about sewer gas, possibly being pulled in to the home, when your system is operating.

    HVAC Condensate drainage/disposal, in the majority of the time, is required to be "Indirect" with an "Air gap separation" as "Your Code" states, & that generally means that it can be drained to Utility Tub, or, a Washing Machine Supply/Drain set up as suggested "IF" it is set up for an additional drain in my belief. On that part of the Plumbing Code, I'm not sure if it would allow for "Alterations". Another option is to run the condensate to a Floor drain via 3/4" Sch. 40 PVC, or to the outside via a Condensate Pump.

    I'm trying to figure out why that "Un-finished" stub, is even protruding through the floor plate, unless it was to have become a Floor drain, or a Vertical Vent. Either way,.. That setup is against Code, Un-ethical, & a outstanding example of "How it shouldn't be done!"

    The other "Problems" are that Your Furnace/AC Condensate are to be ran in 3/4" PVC, as You stated, & which the Pic shows that is not there, but,... Where is the Air Conditioning Trap, is it made up of that hose that is coming from the pan drain? Where is the Condensate trap for the furnace, & where does the Furnace condensate tie in with the AC Condensate?

    Another problem is that your Furnace Combustion Air, is being pulled from that room, & the Furnace exhaust is being vented outside. Does that room have "Fresh Air Intake Vents", or is that 4" pipe hanging there supposed to provide Your "Combustion Air"?

    If enough Fresh Air, is not provided for Combustion, then you will begin to have major issues once it gets cold, not only with your new furnace properly operating but also with the "pressure switch" possibly locking out the burner due to the difference in air pressure &/or lack of Combustion Air.

    Where is the shut off switch for the furnace?

    But back to your AC Drain,... "if", your drain, will not carry the condensate, especially on days of high humidity, then the Evaporator pan will overflow, causing that water to fall upon the furnace Heat Exchanger, Blower, & possibly even the controls. That water could cause a Heat Exchanger Failure resulting in harm to Life &/or property, & the Exchanger would not be Warrantied, due to an improper Installation, that Failed to follow the applicable Codes! That situation also applies to the Blower & controls if they were to Fail.

    I'd go over those Furnace Installations Instructions thoroughly, so as to have an Intelligent conversation with whoever installed your system, & demand that the System be Re-installed according to the Manufacturer's Specs, with a Mechanical/Electrical Inspection from your AHJ.

    "If" the Installer refuses to do that,.... Then QUICKLY hire a Lawyer that has a back ground in deal;ing with matters like this.
     
  16. Terry H

    Terry H In the Trades

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    You can turn a PVC bell reducer upside down here to use for your air gap. I’m honestly not sure if that is written in the 2015 IPC. ACTUALLY, I’m sure that it is.

    What would happen if that sink stopped up? The condensate couldn’t drain. The air gap is there for a reason.

    With that said I probably wouldn’t use an air gap under that sink but would just keep an eye on the sink itself to make sure everything was draining.
     
  17. DavidDeBord

    DavidDeBord New Member

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    Greetings Terry,

    "What would happen if that sink stopped up" <<< Let me clarify that,... The Condensate being run to the "utility sink", drains in to the sink, & is not connected to the sink drain piping.

    We've usually mounted it in such a way that approx. 1 1/2" of the Condensate drain extends out in to the open area of the sink, & it is mounted to the wall in such a fashion that someone using the sink, doesn't smack in to it, nor knock it around as to where it would have water running on to the back of the sink, nor out on to the floor. I had a Cinti., Ohio Inspector suggest this, as the means to dispose of the Condensate about 26 years ago, when We asked for a Preliminary Inspection due to several Issues that had arose about this Installation, due to The HO's "Needs & Wants" (Nit Picking & not being really Co-operative). I used that method, at least twice in Clermont County, Ohio, over the years, & I never had a problem with the Mech. Inspector approving that method.

    I will say this though,... No Plumbing Inspector, as in regards to a proper method of draining, was called for my HVAC Installations, but I did "Assume" that the Mechanical Inspectors knew what they were talking about.
     
  18. wwhitney

    wwhitney Active Member

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    Interestingly, 2015 UPC does not require an air gap when air condition condensate is discharged to a sink tailpiece. 814.6. The tail piece is normally empty except when the sink is draining. I guess if the tailpiece backs up, it is assumed the sink user will notice.

    I haven't checked the IPC.

    Cheers, Wayne
     
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  19. Profound-Tingle-Reoccur

    Profound-Tingle-Reoccur New Member

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    OK, thanks for all of the feedback. I'm hoping to fix this ASAP as it's clear that my current setup is not at all to code.

    Here's a rough mock-up of what I have planned. I bought a Little Giant VCMX-20ULST condensate pump to pump the HVAC condensate one room over and connect it to my bathroom sink above the trap.

    The red line from the furnace to the pump will be 3/4" PVC as per my furnace's manual. Then, as per the pump manual, an inverted "U" trap directly above the pump at the highest point. Then run the included 1/2" vinyl tubing through the wall, behind the toilet, into the vanity and connect it to a wye with a 1/2" branch.

    And of course I'll re-cap the cleanout in the furnace room to prevent backup/sewer gases. Are there any major issues with this plan?
    Condensate line.png
    IMG_0384.jpeg IMG_0382.jpeg
     
  20. wwhitney

    wwhitney Active Member

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    I would think that after the "inverted U" the pipe should slope only downwards. So you'd approach the tailpiece from above, rather than below. I don't think you want standing water in the tubing beyond the initial vertical rise at the pump.

    Cheers, Wayne
     
  21. Jeff H Young

    Jeff H Young In the Trades

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    This is not new stuff we routinely dump condensate to sinks here when I say routinely I mean over 90 percent of them no air gap and sewer gas dosent go into the system any more than it pours up through the drain in the sink Thats why sinks have ptraps. If your pumped line plugs up than you either have a secondary line or a switch in the pump basin that shuts a/c off in event of overflow.
     
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